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40 Cards in this Set

  • Front
  • Back
point mutations
permanent, sudden qualitative alterations that arise as a result of addition, deletion, or substitution of one or more bases in region of gene
spontaneous mutations
mutations that result from chemical and physical components in organism's environment
induced mutations
genetic changes resulting from organism's exposure to artificial physical or chemical mutagen
conjugation
mating process between "sexually" differentiated bacterial strains that allow unidirectional transfer of genetic material
transduction
a bacteriophage-mediated transfer of genetic material from one cell to another
transformation
a genetic alteration in a cell resulting from the introduction of free DNA from the environment across the cell membrane
Ames test
a bacterial test system for chemical carcinogenicity
carcinogenicity
linked to mutagenicity
Salmonella typhimurium
organism used in Ames test with HIS- and BIO-
bacteriophage
virus that attacks bacteria
bacteriophage attachment
adsorbs into bacterial cell surface by means of tail fibers and base plates. injects nucleic acid into the bacterium during penetration (tail sheath contracts, driving the tail core through cell wall)
plaque formation
new phages are released from original infected cell to infect other cells which are lysed - produces a clearing or plaque
salt solution
neutralizes the negative charge of the DNA's phosphate units
detergent (Dawn)
helps to remove cellular membrane and allows access to DNA (emulsifies or breaks up the fats in the cell membrane)
meat tenderizer
destroys enzymes which could digest the DNA; heat enhances this action
ethanol
separation of layers- DNA (white stringy matter) rises into the alcohol layer while protein and cellular debris is in the bottom
biofilms
composed of populations or communities of microorganisms adhering to environmental surfaces
microbial mats
specialized microbial communities composed mainly of photosynthetic prokaryotes
benefits of biofilms
break down organic wastes:
water treatment
septic systems
disadvantages of biofilms
dental carries
contamination of artificial surfaces used to treat patients
resistant to antibiotics
biofilm formation steps
1. reversible adsorption of bacteria (forms sticky layer)
2. irreversible attachment of bacteria (becomes planted)
3. growth and division of bacteria
4. exopolymer production and biofilm formation
5. attachment of other organisms to biofilm
operon
a unit made up of linked genes that is thought to regulate other genes responsible for protein synthesis. consists of a promoter, an operator, and the structural genes they control
promoter
the region where RNA polymerase binds
operator
signals whether transcription will occur
nar operon
encodes E. coli genes for nitrate reductase
ara operon
encodes E. coli genes for catabolism of arabinose
bioinformatics
branch of science devoted to computational information management systems used to collect, store, analyze, and disseminate biological information - identification and classification of bacteria
16s rRNA DNA segment
easily compared because found in all organisms with the same function
rRNA gene sequencing advantages
1. all cells contain ribosomes and rRNA
2. greater relation equates to fewer differences in sequences
3. RNA genes are highly conserved
4. does not require cell to be cultured
signature sequences
5-10 base pair sequence always found in a particular group of organisms - specific location in sequence
biosafety levels: level 1
organisms not known to cause human disease; minimal hazard
biosafety levels: level 2
agents of moderate potential hazard
biosafety levels: level 3
clinical, diagnostic, teaching, research with indigenous agents; serious hazard - like leprosy
biosafety levels: level 4
exotic organisms; life threatening disease potential & no vaccines - like Ebola
PCR (polymerase chain reaction)
tool for amplifying a single nucleic acid sequence of DNA or RNA until there is enough material to detect and identify the source
steps of PCR
1. heat denaturation
2. annealing of primer pair
3. primer extension
differential medium
a medium that distinguishes between multiple bacteria by appearance of colonies grown on a plate. for example, colonies of various bacteria may be colored differently.
selective medium
a medium that suppresses growth of one type of bacteria, but permits the growth of other kinds of bacteria
chemically defined media
made from known amounts of pure chemical compounds
artificial/complex media
commonly used and works for most bacteria. exact chemical composition is not known.

ex: nutrient broth, yeast extract broth